Double-lumen tubes and auto-PEEP during one-lung ventilation

Spaeth, J.
Ott, M.
Karzai, W.
Grimm, A.
Wirth, S.
Schumann, S.
Loop, T.
Thompson, J. P.

¹Department of Anaesthesiology and Intensive Care Medicine, University Medical Center Freiburg, Hugstetter Str. 55, Freiburg 79106, Germany, and ²Department of Anaesthesia, Intensive Care and Emergency Medicine, Zentralklinik Bad Berka, Robert-Koch-Allee 9, Bad Berka 99437, Germany

^*Corresponding author. E-mail: [email protected]

accepted September 15, 2015; previously published online December 16, 2015

BJA: British Journal of Anaesthesia 116(1):p 122-130, January 2016. | DOI: 10.1093/bja/aev398

Abstract

Background:

Double-lumen tubes (DLT) are routinely used to enable one-lung-ventilation (OLV) during thoracic anaesthesia. The flow-dependent resistance of the DLT's bronchial limb may be high as a result of its narrow inner diameter and length, and thus potentially contribute to an unintended increase in positive end-expiratory pressure (auto-PEEP). We therefore studied the impact of adult sized DLTs on the dynamic auto-PEEP during OLV.

Methods:

In this prospective clinical study, dynamic auto-PEEP was determined in 72 patients undergoing thoracic surgery, with right- and left-sided DLTs of various sizes. During OLV, air trapping was provoked by increasing inspiration to expiration ratio from 1:2 to 2:1 (five steps). Based on measured flow rate, airway pressure (P_aw) and bronchial pressure (P_bronch), the pressure gradient across the DLT (ΔP_DLT) and the total auto-PEEP in the respiratory system (i.e. the lungs, the DLT and the ventilator circuit) were determined. Subsequently the DLT's share in total auto-PEEP was calculated.

Results:

ΔP_DLT was 2.3 (0.7) cm H₂O over the entire breathing cycle. At the shortest expiratory time the mean total auto-PEEP was 2.9 (1.5) cm H₂O (range 0–5.9 cm H₂O). The DLT caused 27 to 31% of the total auto-PEEP. Size and side of the DLT's bronchial limb did not impact auto-PEEP significantly.

Conclusions:

Although the DLT contributes to the overall auto-PEEP, its contribution is small and independent of size and side of the DLT's bronchial limb. The choice of DLT does not influence the risk of auto-PEEP during OLV to a clinically relevant extent.

Clinical trial registration:

DRKS00005648.